This thesis describes the development, verification and application of a new practical computer based explosive selection technique. It is designed to assist drill and blast engineers in the selection of the most appropriate type of explosive for a particular blasting situation at surface mining operations.
The choice of an explosive is of primary significance as it is the explosive that is responsible for breaking and displacing the rock. The problem for any mine is the selection of the optimum explosive, that is the explosive that adequately breaks and displaces the rock at the lowest possible cost. A broad survey of available techniques for explosive selection highlighted a variety of limitations. It was these limitations that prompted the need for the development of a new technique.
A fully documented modular interactive spreadsheet program called "Designer" was developed for explosive selection. The program uses data on the blast geometry, explosive distribution, rock properties, explosive properties and blasting cost to predict explosive performance in terms of fragmentation, heave and cost. A modified form of the Kuz-Ram model was used to calculate the fragmentation size distribution and a new two dimensional muckpile profile model was used to determine the shape of the muckpile.
Further modifications were made to the Kuz-Ram model by extending the definitions of the "Rock Factor" and "Energy Factor" in the model. The Rock Factor considers the effect of rock structure in terms of a mean in situ block size as determined from a new in situ block size distribution model. The Energy Factor has been modified to include the effect of non-ideal detonation explosive behaviour using a simple non-ideal model and results from a new velocity of detonation prediction model. The muckpile shape is calculated using a modification of a reduced efficiency equation originally developed to predict products for mineral processing applications.
Preliminary results from a case study indicated that Designer gave realistic and practical information about the fragmentation and heave potentials of an explosive. It was applied successfully to determine the most suitable explosive type for a particular blasting situation based on its blast fragmentation, heave and cost. It was also found that the calculations and displays are easily operated by the user and required little computing time.
Although preliminary results indicated good agreement between measured and predicted results, a significant amount of field application, further testing and verification should now occur. Designer represents a powerful, practical, accessible and easy to operate technique for assisting drill and blast engineers in the selection of the most suitable explosive at surface mining operations. This technique allows for explosive selection in the “office" thus reducing the need of large numbers of laborious, expensive and inconvenient field trials.